Ring size in octreotide amide modulates differently agonist versus antagonist binding affinity and selectivity.
J Med Chem
; 51(9): 2676-81, 2008 May 08.
Article
em En
| MEDLINE
| ID: mdl-18410083
ABSTRACT
H-DPhe (2)-c[Cys (3)-Phe (7)-DTrp (8)-Lys (9)-Thr (10)-Cys (14)]-Thr (15)-NH2 (1) (a somatostatin agonist, SRIF numbering) and H-Cpa (2)-c[DCys (3)-Tyr (7)-DTrp (8)-Lys (9)-Thr (10)-Cys (14)]-Nal (15)-NH2 (4) (a somatostatin antagonist) are based on the structure of octreotide that binds to three somatostatin receptor subtypes (sst 2/3/5) with significant binding affinity. Analogues of 1 and 4 were synthesized with norcysteine (Ncy), homocysteine (Hcy), or D-homocysteine (DHcy) at positions 3 and/or 14. Introducing Ncy at positions 3 and 14 constrained the backbone flexibility, resulting in loss of binding affinity at all sst s. The introduction of Hcy at positions 3 and 14 improved selectivity for sst 2 as a result of significant loss of binding affinity at the other sst s. Substitution by DHcy at position 3 in the antagonist scaffold (5), on the other hand, resulted in a significant loss of binding affinity at sst 2 and sst 3 as compared to the different affinities of the parent compound (4). The 3D NMR structures of the analogues in dimethylsulfoxide are consistent with the observed binding affinities.
Texto completo:
1
Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Octreotida
/
Receptores de Somatostatina
Limite:
Humans
Idioma:
En
Revista:
J Med Chem
Assunto da revista:
QUIMICA
Ano de publicação:
2008
Tipo de documento:
Article
País de afiliação:
Estados Unidos